Cadillac: 83 Cadillac Deville, pressure gage, cadillac deville

Question
 When ever im driving down a highway for 15 minutes or so.  My 83 Cadillac Deville will begin it "bog out".  I have to lt off the accelerator and slowly ease down.  Eventually if I drive to far doing this my car will stall and I am forced to pull over.  I was told that water in the gas may be a probem but I have a feeling thats not it.

Answer
Sounds more like a failing fuel pump. Put an external fuel pump pressure gage on the engine fuel rail and tape it to the outside of the windshield so you can watch to see if the fuel pressure starts to drop the hotter the engine gets. If it does, replace the pump in the fuel tank./